Literature Review on Building Envelope, Heating and ... - Beeshive.org

facing windows could result in overheating in late March or September when the sun is
relatively low in the sky and outside air temperature is higher than about 21°C (70°F). To
address the overheating issue, few windows are opened. Opening windows at night keeps
the house cool in summer.
Airtight Construction: Air sealing was a high priority. A polyethylene membrane
served as both an air barrier and vapour retarder on the walls and ceilings. Foam-in-place
polyurethane was used at all penetrations, and sealant was used at framing connections.
Neoprene boots sealed plumbing stacks. The envelope measured air tightness was 0.37
ach at 50 Pa or 65 L/s (137 cfm) at 50 Pa.
Ventilation: A central HRV supplies fresh air into the return air ductwork.
Heating System: A drain-back active solar system heats the house. This includes a 33 m 2
(360 sq. ft.) collector built on site and a 4500 litres (1200 gallon) storage tank. A 52-
gallon electric water heater is used for backup heat and domestic hot water. A water-toair
heat exchanger in the forced-warm-air delivery system extracts heat from the storage
tank of the solar system to heat the house. When there isn’t enough heat in the storage
tank, the electric water heater (with a 5 kW element) takes over. The electric water heater
was metered separately to collect data on the energy consumption of each energy source.
Lighting and Appliance Efficiency
The use of compact fluorescent lighting, halogen lighting on dimmers, and the selection
of efficient appliances helped reduce the energy load on the house.
Sustainable Features included:
• Grey water separation: The house was plumbed so grey water (wastewater from
showers, bathroom sink, and washing machines) could be collected separately if
regulations change. Regulations at the time of the house construction (1994) did not
permit grey water treatment by individuals.
• Efficient use of environmental resources: Very little lumber from large-diameter
trees was used. Trusses and I-joists were used for framing members larger than 38 x
89 mm (2 x 4). Oriented strand board was used for sheathing and sub-floors.
• Built for durability: The house was constructed to be very durable through careful
selection of materials and attention to moisture and airflow in the home.
Indoor Air Quality Features included
a continuous supply of fresh air;
• the use of low- or zero-formaldehyde wood composites;
• flooring of hardwood, tile, or natural linoleum instead of carpeting or vinyl, and
counters of granite rather than laminate;
• only water-based finishes used to avoid the generation of VOCs;
• no combustion of wood or fossil fuels on the site; and
an installed passive radon stack. An in-line fan could be added should high radon levels ever
be found.
PERD-079: Task 2 - <strong>Literature</strong> <strong>Review</strong> 68